Wash for sand cores and molds for metal founding



Patented Dec ltd, 1020 WASH FOR SAND CORES AND IVIOLDS FOR METAL FOUNDING.

No Drawing.

My improved wash is particularly adapted for steel castings but it may be used with advantage in making castingrs of other metals. The present practice is to use a wash made by mixing silica (SiO) with molasses. In the use of a wash of this character frequently the material of the wash sticks to the metal when the same is poured. and it is difficult to clean the castings when removed from the mold. "It is also difficult to finish a casting when such a wash has been 4 used because of the formation of the ironsilicates on the surface ofthe casting. the finishing tools becomingquickly dulled on account of the hardness. This adds to the time and the labor required for turning out a finished castinL.

The object which I have in View is the provision of a wash which will cause the casting to be readily cleansable and which will impart to the casting a soft aluminumalloy surface which is easily cut in the tinishing operation.

For this purpose I have invented a new and improved wash characterized by the presence of bauxite or alumina'oxide More particularly my wash is formed of a composition of bauxite and organic oil and a binder.

The organic oil is preferably a vegetable oil. and I have found satisfactory linseed oil or soya bean oil.

For a binder I have successfully used sulphite pitch. molasses or dextrine.

The proportions which I find to be advantageous are approximately one hundred pounds of bauxite not more than three pounds of oil. and not more than three pounds of binder.

In preparing the wash I prefer to first -mix the binder and oil together and then add the bauxite in small quantities together with suflicient water so that as it is stirred Application filed November 16,1925. Serial No. 69,513.

a composition of putty like consistency is obtained. The wash composition may be packed and shipped in this form.

When the wash is to be gotten ready for use itis mixed with sufficient water to obtain a composition of paint like consistency which can be readily brushed or sprayed on the cores or molds.

If desired, of course, in making the origi nal mixture sufficient Water may be employed to obtain a paint like consistency instead of a putty like consistency. but where the wash-compound is prepared at a factorv for shipment to the foundry, it is preferable to produce the putty like form, as it can be more advantageously barreled or otherwise packed for delivery.

The fusingpoint of bauxite or aluminaoxide is approximately 3200 degrees Fahn, while that of steel in proper molten form for pouring is approximately 2700 degrees Fahr. As a result the bauxite does notfuse in the presence of the molten steel and therefore there is no burning in of the materials of the wash in the steel of the castinc. 7 When the casting is removed from the mold there is found deposited on the surface thereof a thin layer of bauxite which being relatively soft is easily and quickly rem ved by a sand blast or by the finishing tool.

What I desire to claim is 2- l. A wash compound for foundry cores and molds comprised of alumina-oxide, a binder and organic oil.

2. A wash compound for foundry cores and molds comprised of aluminaoxide, a binder and organic oil in substantially the proportions of three pounds'each of the binder and the oil to one hundred pounds of alumina-oxide.

Signed at Pittsburgh, Pa, this 13th day of November. 1925.

' EDWARD D. FROHMAN. 

